Sulfone polymers are high performance amorphous thermoplastic engineering resins that contain the characteristic diaryl sulfone linkage. Sulfone polymers are known for their high mechanical strength, thermal and oxidative resistance, resistance to hydrolysis, and to many acids, bases, and solvents.
Polysulfones are well-known high temperature amorphous engineering thermoplastic resins. Among the many desirable physical characteristics and attributes of polysulfone, this polymer is transparent in its natural state. The transparency of polysulfone is useful in combination with its high heat, hydrolysis resistance and other high performance attributes. Examples of uses where the transparency is useful include covers and lids for hot serving dishes and containers, lids for medical sterilization trays, research lab animal cages, dairy processing equipment, flow meters and sight glasses for chemical process equipment.
It is known however that polymerization reactions, including those used to manufacture polysulfones, may not proceed to completion thus leading to the presence of unreacted residual monomer in the polymeric material. Besides affecting polymer properties, residual monomers can also be of concern in view of emerging regulatory considerations. Therefore, complete conversion of monomers is usually the desire of any polymer producer but is often not attainable.
Additionally, when subjected to certain conditions, polysulfones may also undergo degradation, especially under harsh conditions, potentially resulting in the formation of phenolic degradants or reaction products. The resulting degradants commonly correspond to the monomeric starting materials initially used to manufacture the polysulfone.
To that end, there remains a need in the art for thermoplastic polysulfone compositions whose residual monomer content, if any, and whose degradation products exhibit certain beneficial characteristics. Desirable characteristics of such residual monomer or degradants include, among others, relatively little or even no estradiol binding activity.